摘要:

The construction of a vacuum insulated siphon for filling the cold plate of a dilution refrigeration cryostat is described. The siphon allows the pickup of liquid helium from the main liquid‐helium bath at a level 30 cm below the main flange of the dilution refrigeration insert.

ISSN:0034-6748    

DOI:10.1063/1.1137876

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

This paper describes a novel laser system which can give picosecond pulses with greater than 1 MW of power and at a repetition rate of 5 kHz.

ISSN:0034-6748    

DOI:10.1063/1.1137877

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

Modifications required in the circuit described by Pathaketal. [Rev. Sci. Instrum.54, 482 (1983)] to make it select any two echoes rather than two successive echoes for ultrasonic attenuation measurement are described in this note.

ISSN:0034-6748    

DOI:10.1063/1.1137878

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

A sample holder is described by which samples may be alternatively heated in front of a cylindrical mirror analyzer by electron bombardment. Damage to the specimen and high secondary electron yield are eliminated.

ISSN:0034-6748    

DOI:10.1063/1.1137879

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

A high‐temperature specimen holder for use with a commercially available rapid specimen introduction device on an Auger electron spectroscopy system is described. Necessary (nondestructive) modifications to the specimen carousel are also included. Use of the specimen holder allows rapid transfer of specimens forinsituheating to approximately 1000° C during Auger analysis, while retaining conventional capabilities of the commercial system for ambient temperature analysis.

ISSN:0034-6748    

DOI:10.1063/1.1137880

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

The NBS long‐wave acoustic flowmeter has been tested on room‐temperature airflow in a closed pipe to 1.4 kg/s and found to have a sensitivity error of −0.8% and an offset of 2.3 g/s.

ISSN:0034-6748    

DOI:10.1063/1.1137881

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

The heat transport between liquid3He and five different small metal particle ‘‘sintered’’ sponges are directly compared in the temperature range from 7 to 70 mK through measurements on five cells which are identical in every way except for the nature of the sponge. Fine (0.1–1 &mgr;m) powders of copper, silver, and palladium are formed into sponges that are bonded to the walls of a copper container using various packing and heat‐treatment techniques. Each container, fitted with a resistance thermometer and heater and filled with liquid3He at a pressure varying from 3 to 15 bars, is then used as a heat exchanger between a dilution refrigerator and the3He. The palladium sponge, per unit surface area, has the lowest thermal resistance (R) to liquid3He, but is the most difficult heat exchanger to make. The silver sponge, per unit volume, has the lowestRand is by far the simplest heat exchanger to build, requiring only cold packing with no heat treatment, yet performs as well or better than those discussed previously in the literature.

ISSN:0034-6748    

DOI:10.1063/1.1137882

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

A gas thermometer operated diaphragm valve for controling LN2transfers is described. The value uses the pressure variation of air or N2between 77 K and ambient temperature to open and close the vent line of a self‐pressuring storage Dewar.

ISSN:0034-6748    

DOI:10.1063/1.1137883

出版商:AIP    

年代:1984

数据来源: AIP